Long Term Evolution (LTE) networks operate in a number of specific frequency bands and deliver a wide variety of information to an ever-increasing number and type of user equipment (UE). Typically, the use of different communication techniques is limited to licensed bands regulated by the federal government. The growth of network use has sparked an interest in expanding LTE use beyond these licensed bands. LTE-Unlicensed (LTE-U) allows UEs to make use of unlicensed spectrum in communications. Other networks, such as WiFi and Bluetooth, coexist with LTE-U in the unlicensed spectrum. This presents a problem as periodic reference signaling messages occur between the LTE network and UEs. The reference signaling messages may include a cell-specific reference signal (CRS), which is used for scheduling transmissions to multiple UEs and for channel estimation used in coherent demodulation at the UE. The reference signaling messages may include a Channel Quality Indication (CQI) indicating a measurement of the channel quality, a channel state information reference signal (CSI-RS) used for measurement purposes, and a Discovery Reference Signal (DRS) specific to an individual UE. These and other periodic messages thus not only provide information regarding the communication channel, but also enable tracking in time and/or frequency of communications with the UE. These periodic messages may cause issues in communications between WiFi and Bluetooth devices and/or cause additional interference in the communications between the WiFi and Bluetooth devices. Moreover, due to the nature of transmissions in the unlicensed band in contrast with the ordered transmissions in a licensed band, some of the periodic messages may not reach the intended UEs.
It would therefore be desirable to provide an efficient signaling mechanism for LTE-U devices while minimizing disturbances to other devices operating in the same unlicensed spectrum.